"Risperidone (trade name Risperdal, and generics) is an atypical antipsychotic drug which is mainly used to treat schizophrenia (including adolescent schizophrenia), schizoaffective disorder, the mixed and manic states associated with bipolar disorder, and irritability in people with autism.
Risperidone belongs to the class of atypical antipsychotics. It is a dopamine antagonist possessing antiserotonergic, antiadrenergic and antihistaminergic properties.
Side effects of risperidone might include significant weight gain and metabolic problems such as type 2 diabetes mellitus, as well as tardive dyskinesia and neuroleptic malignant syndrome. Risperidone and other antipsychotics also increase the risk of death in patients with dementia.
The drug was developed by Janssen-Cilag, subsidiary of Johnson & Johnson, and first released in 1994. Today many generic versions are available."